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Samples of humic materials—humic acids and fulvic acids—derived from Tisul lignite (Kansk-Achinsk Basin) are investigated by ESR (electron spin resonance) spectroscopy. The concentration of free radicals declines in the following sequence: lignite, humic acids, fulvic acids. The proportion of aliphatic radicals increases in the same sequence. By simulation of the ESR spectra of the fulvic acids and comparison with the experimental spectra, natural complexes of fulvic acids with Fe3+ and Mn2+ ions are detected. By determining the splitting parameters in zero field (D and E), it is established that the complexes with Fe3+ have axial symmetry, with a complex multilevel structure. The internal coordination sphere of the complex consists of water molecules, whereas the external coordination sphere consists of oxygen-bearing fulvic acid groups. The calculated hyperfine structure constant of the experimental ESR spectra for the complexes with Mn2+ (79.7 G) is lower than the typical value for the octahedral Mn2+ complex [Mn(H2O)6]2+. That indicates partial replacement of the water molecules by oxygen-bearing functional groups of fulvic acids. [ABSTRACT FROM AUTHOR]

The thermal conductivity of liquid alloys of the cesium–bismuth system with 20–66 at % Bi in the temperature range from the liquidus line to 1173 K has been studied experimentally with an error of 4–6%. It was found that the thermal conductivity of liquid cesium bismuthides for the indicated compositions and temperatures takes low values from 0.7 to 4.5 W/(m K) typical for liquid salts. The thermal diffusivity and Lorenz number were calculated from the results of thermal conductivity measurements. An analysis of the temperature and concentration dependences of the studied properties indirectly confirms current views on the presence of ordered structures called ionic complexes in alkali metal bismuthide melts, which significantly affect the thermophysical properties of melts and are destroyed at elevated temperatures. [ABSTRACT FROM AUTHOR]

Below, the possibilities of computer modeling are used to explain the experimental data obtained by us (pulsating rays in a mixture of propane air). With the use of the computer mathematical program MATHCAD, the role of the heat released during the decomposition of ozone molecules, induced by ionic molecules and surface ion-frozen active centers (H2⋅Cl–), into ozone molecules, the self-decay of which highly heats the medium, and resulted in the birth of both concentration traveling waves and weak shock waves in reactors. [ABSTRACT FROM AUTHOR]

The thermal conductivity and thermal diffusivity of liquid alloys of rubidium–bismuth systems with Bi contents of 27.0, 50.0, and 66.7 at % are studied in the range of temperatures from the liquidus line to 1173 K using laser flash method. Equations are obtained for approximating the studied properties. Analysis of the temperature and concentration dependences of thermal conductivity and thermal diffusivity indicates the presence of ionic complexes in Rb–Bi melts that decompose as the temperature rises. [ABSTRACT FROM AUTHOR]

The complexes [PhPR][OsBr], R = cyclo-CH ( I), n-CH ( II), cyclo-CH ( III), CHC(O)Ph ( IV), [PhPPr][OsBr] ∙ DMSO ( V), and [PhP(CH)PPh][OsBr] ∙ DMSO ( VI) (CIF files CCDC nos. 1000171, 1000148, 1000172, 1000173, 1000147, and 1000149 for structures I-VI, respectively) were prepared by reactions of sodium hexabromoosmate with phosphonium bromides in dimethyl sulfoxide. According to X-ray diffraction data, phosphorus atoms in the cations have slightly distorted tetrahedral coordination (CPC angles, 105.2(3)°-115.5(3)°; P-C, 1.773(6)-1.814(6) Å). In the octahedral [OsBr] anions, the Os-Br bond lengths are 2.4734(8)-2.5203(5) Å and the cis-BrOsBr and trans-BrOsBr angles are 88.38(2)°-91.53(3)° and 177.276(18)°-180°, respectively. The structural organization in the crystals is formed by H∙∙∙Br (2.74-3.04 Å) and H∙∙∙O (2.28-2.63 Å) ion-ion hydrogen bonds. [ABSTRACT FROM AUTHOR]

The impact of the association of lithium cation with NCS ion in acetonitrile on the vibrational spectrum was studied by the density-functional method in the B3LYP/6-31+G(d,p) approximation. The best agreement between experimental and calculated ionic association data was achieved taking into account the nonspecific solvation, oversolvation, and solubility of ionic complexes within the discrete-continuum model. The microstructures of the thiocyanate ion in a contact ion pair with lithium cation and ion-pair dimer and trimer in acetonitrile were established. [ABSTRACT FROM AUTHOR]

Structural and thermodynamic characteristics of molecular and ionic complexes of aluminum trichloride with pyrazine (pyz) and 4,4′-bipyridyl (bipy) are calculated at the RI-BP86/def2-SVP level. It is found that for molecular 2AlCl·3L and 4AlCl·3L complexes an energy difference between isomers does not exceed 4 kJ/mol, and the rotation barrier of the AlCl moiety relative to the N-Al-N bond does not exceed 24 kJ/mol. A comparison of the stability of molecular and ionic complexes of aluminum in the gas phase shows that the maximum energy difference is ∼60 kJ/mol. For L = pyz the molecular complex is more stable whereas for L = bipy it is the ionic one. [ABSTRACT FROM AUTHOR]

Density functional PBE/TZ2p quantum chemical calculations of activated complexes and pathways of model catalytic transformations of propane under the action of aluminum chloride-cobalt chloride ionic bimetallic complexes were carried out. The formation of an intermediate with a broken C-C bond can occur on the cationic cluster CoAlCl characterized by the strongest coordination of propane molecule. The activation barrier to the reaction is Δ G = 25.0 kcal mol. Activation of alkane C-H bonds follows the alkyl pathway involving the formation of bimetallic alkyl complexes. The interaction of activated hydrocarbon fragments bound to transition metal atoms in cobalt-chloroaluminate clusters can result in alkane metathesis products (in this case, ethane and a polymetallic cluster containing an extendedchain alkyl radical). [ABSTRACT FROM AUTHOR]

Density functional calculations of binary and ternary propane complexes with aluminum and cobalt(II) chlorides were carried out. Interaction of metal chloride complexes with the methylene and methyl groups of propane is coupled with strong polarization of C-H bonds. The direction of polarization is opposite to that observed under interaction with the typical Lewis acids including aluminum halides. In the interaction of bimetallic (transition metal/aluminum) complexes with saturated C-H bonds, the key role is played by the transition metal ion rather than the stronger Lewis center (Al). The negative atomic charge on carbon increases, which may facilitate the formation of metal-alkyl compounds with a carbanion-type organic radical. [ABSTRACT FROM AUTHOR]